A shallow underwater acoustic field study was conducted south of Martha’s Vineyard in the New England Mudpatch in 2017. The experimental area was unique in the sense that the bottom consisted of a layer of mud, of spatially varying thickness, overlaying layers of sandy and silty sediments. In situ measurements indicate that the sound speed in the mud is less than that in the overlaying water column. One experimental component involved the deployment of broadband sources spatially distributed in the experimental area. Pressure and particle velocity data acquired on hydrophones and geophones will be analyzed. The modal dispersion in the frequency band 10 Hz to 300 Hz will be investigated for modal dispersion. High-resolution time-frequency analysis techniques will be used to calculate the modal arrival times. The differences in the modal dispersion at various azimuths will be investigated using different source-receiver propagation paths. Normal mode and parabolic equation models (Monterey-Miami Parabolic Equation (MMPE) model) will be used to model the modal arrivals and compared with the data. [Work supported by the U.S Office of Naval Research]